Improvement in computing-tablet



' thinned lteres anni (Militia.

HENRY KUMMER, YORK, N. Y.`

Letters Patent No. 90,275, dated May 1S, 1869.

IMPROVEMENT IN COMPUTINGhTABLBT.

The Schedule referred to in these Letters Patent and making part of the same,

To all whom 'it may concern which additionsand subtractions can be executed with.

great rapidity and'exactness, and Vwhich also facilitates the operationsof multiplication and division.

It is constructed on the principle of the adding-machine, described in Letters Patent granted to Samuel Young, July 24, 1849, being composed of a flat slotted tablet, numbered with several rows of figures, and provided witha series of slides, by the aid of which the calcmating-operations are effected.

My invention consists in the arrangement of whatl term carrying-angles in thetablet, and of open slots inthe edges of the slides, in .addition to the holes in said slides, in'such a manner, that by means of said carrying-angles and open slots, the, pin, which serves to operate the `slides, can be readily passed from one slide to the adjoinngone, without withdrawing its point, and thereby the operation of "Icarrying7 a figure from one slide to the next is materially facilitated, and can, in many eases, be performed without withdrawing the pin from the slides. f. Y The tablet is provided wit-h two sets of slots andV carrying-angles, one set for addition and multiplication, and the other set for subtraction and division, and between the two sets of slots are apertures, or windows, through which the result of the calculation can be read off.

Two transverse slides, near the bottom edge ofthe tablet, are used in addition to the longitudinal slides,

for the purpose of`\executing multiplications and divis-` ions.

A represents a tablet, made of sheet-metal, or any other suitable material, and provided with two sets of slots, a b, one set, a, of' which starts at or near the top edge of the tablet, and terminates in carrying-angles c, somewhat above the middle of said tablet, while-the other set of slots, b', starts at the lower part of the tablet, and terminates somewhat below its middle, in the carrying-angles7 cl.

-The upper set of slots serves forexecuting additions and multiplications, and the lower.set for executing subtractions and divisions, the resultin either case being read olf through apertures, or windows e, between the upper and the lower carrying-angles.

On the sides of the'slots are marked the figures l, 2, 3, 4, 5, 6, 7, 8, 9, one above the other, as shown in fig. l of' the dra'wing, the figures on the upper slots a 'running from top down, and those on the lower slots l? 'from the bottom up.

There are two slots, YL* bt, shorter than the rest, and on the sides of these slots are marked the fractions and or any other convenient series of fractions.

To the under surface of the tablet A are lit-ted a series of slides, B, equal in number to the slots a, and ext-ending throughout the entire length of the tablet, under the slots a. and b, as shown in fig. 2 of the drawing. 'lhcse slides are held imposition by suitable traverses f, attached to the under surface of the tablet,

and ,they are prevented from moving spontaneously by friction-springs y. .l

Each slideis provided with nine holes, 'i-, commencing near its upper end, and corresponding in position (when the slide is pushed home) to the figures 1,2, 3, 4, 5, 6, 7, S, 9, -on the slots a, and it is also provided with nine similar holes, j, commencing' near its bottom end, and corresponding in position (when the slidel is drawn out) to the figures l, 2, 3, 4, 5, 6, 7, 8, 9, on the slots b.

The space between the two sets of' holes on each slide is occupied by open slots k, and when one of the slides is drawn out, said open slots may take the places of' the holes, corresponding in position to the figures on the sides ofthe slots a and b.

That portion of' each slide which is occupied by the open slots k is increased in width, so that the edges of` said wide portions of' the several slides are close to gether, (see fig. 2,) and each slide is provided with a series of open slots, l, on that edge which is opposite 'to the open slots k, each of saidopen slots' l being exactly opposite to one of'- the open slots, ls,- l

The slide B*, under the fraction-slots a* bi, is constructed similar to the.- slides B, with the exception that the number of holes therein is confined to the number of' fractions placed on the sides of said slot-s, and the'num'ber and position of' the open slots between said holes are controlled'by thenumber and position ofthe holes. y Y

. In using my calculator for executing an addition or subtraction, I proceed as follows:

The slots a and b may represent units, tens, hundreds, Ste., or they may represent lc., 10c., S1, S10, 85o., as indicated by the figures ,on the ends of said slots.

In adding up the following/example:

- S27 30% s 94s A 7 l proceed as follows: The slides are first set to their starting-points. I then take a pointed piece of wire,

or other material, and insert it into the hole opposite the ligure on the fraction-slide, and carry said slide up, until the-pin strikes the upper end of the slot. Then insert the pin into the hole opposite the ligure 3, on the 10c. slide, and move that slide. Then do the same on the $1 and $10 slide, and by these means the figure 27 30% will appear in the windows. Next insert the pin into the slot opposite -the on the fraction`slide, and carry this slide down, the rule being that Vthe slide is carried up when a' hole is opposite the figure t0 be added, and down when an open slot is opposite said figure, and in this latter case one has to be carried on the next adjoining slide.

This purpose is effected by carrying the fraction-slide dbwn, until the pin strikes the bottom end of the slot, and then moving the pin sideways into the carryingangle, and up until it strikes the upper end of said angle. The'iaction-window then shows i, and the 1c. window a 1. Next take the 4, on the. 1c. slide; then the 9, on the 10c. slide, carrying one tov the $1 slide; then the 8,- on the $1 slide, carrying one to the $10 slide, whereby the windows are made to exhibit the figure 36 25%. Finally, add the 7, on the $1 slide, carrying 'onel to the $10 slide, which gives the result, viz, 43 253;. 1

In-some eases, it happens that the slide on which one is to be carried is already clear up, (showing a 9 in its window,) and in such case such slide is brought clear down, and the one is carried von the succeeding slide; for instance, in adding- 1998 Y the 1c., 10c., and $1 slides are first set to show 999.

Y By adding thereto the 9 of the second figure, the 1c.

slide is carried down, and made to show 8 in its window; but in order to carry the F one, the 10c. and $1 slides have to be moved clear down, and the' one"can then be carried on the $16 slide, showing 1008 in the:

windows. Then the two` remainingfQs are addedon the 10c. and $1 slides, and the result is 1998;

In making a subtraction, the operation is as follows:

Suppose $13 87are to'be subtracted from $43 2.5i.

Set the slides so as to exhibit in the windows the last-- named figure, (43 25%,) insert the pin into theslot oppositie the on the lower portion f the fraction-slide, and move upward toward the carrying-angle, and carry one, by moving 'the piu into thecarrying-angle, and down, so as to vshow in the window of the fractionslide, and 4'ingthe window of the lo. slide. Then insert the pin into the slot opposite the 7, on the 1c. slide, move up toward the carrying-angle, and carry one, on the 10c. slide, making the figure in the windows 43 17%. Then insert your pin in the slot opposite the 8, on the 10c. slide; move up and carry oneA on the $1 slide, making the figure` in the windows 42 37%. Then insert your pin in the slotvoppositethe ligure 3, on the l$1 slide; move up, and 'carry one on the $10 slide, making the figure in. the windows 39 37%; and, finally, insert your piu into the hole opwill be readily appreciated.

posite the 1, on the $10 slide, and move down, making the result oi' the operation '29 4371g.

This operation is carried on on the lower, or subtraction-half ofthe tablet, and' whenever the ligure to beV subtracted stands opposite a hole on its slide, said slide is moved down, aud when .it stands opposite to an open slot, the slide is moved up, and one is carred on the succeeding slide, by moving the pin into the carrying-angle, and down therein, until it strikes the bottom thereof.

The multiplication and division are carried on by means of the transverse slide 1), and strip E, at the bottom of the tablet-A.

If it is desired to multiply 54 by 32, the multiplicand, 54, is written on the slide D, so -that the 5 is under the 10c. slide, and the 4 under the 1c. slide.' The multiplier, 32, is then written on strip E, bringing the 3 under the 5, and thel 2 under the 4. Then proceed as follows: 2 times 4 make 8', which indicate on the 1c.

addition-slide; 2 times 5 are 10, which indicate on $1 addition-slide; then move the slide.D, so as to bring the 4 over the 3, and proceed in the same manner, 3 times 4 are 12, which mark onthe 10c. andl $1 slides;

3 times 5 are 15,which mark on the $1 and $10 slide,

and the result, 1728, will appear in the windows. L'

In making a division, the subtraction-slides come intouse. If, for instance, 228 are to be divided by 12, 1 set the slides so that the windows show the dividend, 228. The-n I move the slide D under the word division, on the tablet, and write Athereon the divisor, 12, under the 100 and $10 slides, which show the 22. Then proceed as follows: 12 is contained in 22 once; mark 1 on the strip E, and subtract l2 from 22 by moving the proper subtraction-slides, which leaves in thawindows the figure 108,12 in 108,9 times; write 9`on the strip E, under the 2 ofthe divisor; 9 times 1 2 are 108; subtract 108 from 108, which leaves noth` ing in the windows of th`e tablet;

From these examples, it will be readily understoo how my calculating-machine is to be used, and itsgieat advantage particularly in adding. long rows of igures I disclaim everything shown and described in the lpatent granted to Samuel S. Young, July 24,1849 but Having thus described my invention,

'What I claim as new, and desire to secure by Letters Pateut,fis 1. The carrying-:inglesa d, in combination with the` slots a b, in the tablet A, and with the slides B, substantially as set forth.

2. The arrangement of open slots k and holes 13j, iu the slides B, as described., l

3. The arrangement of open slotsl in the slides op` posite the open slots k therein, substantially in the manner set forth.

- HENRY KUMMER'.

Witnesses:

W. HAUFF, O. WAHLERS. 

